Aston Martin's chief executive Ulrich Bez has just done what his former employer Porsche would not do - and he has turned up at the Geneva motor show to tell the world about it.

Aston Martin's four-door coupe could arrive years before Porsche's

Mr Bez is here to show off the British carmaker's latest concept, a sleek four-door, four-seat coupe, kitted out with a 5.9-litre V12 engine that will make it more than able to live up to its name: Rapide.

"When I was [working for Porsche] I designed a similar car," Mr Bez tells BBC News, referring to his time as head of product design and development at Porsche.

That was during the early 1990s, when Mr Bez was convinced the market was ready.

Mr Bez insists the project was only shelved after his departure in 1993, when "the marketing people said, 'No-one will buy this car'," though industry officials suggest the design met plenty of resistance long before he left.

Different league

Porsche has since changed its mind, though. Last year, it said it intended to build the Panamera - a four-door, four-seat saloon - after all.

Ulrich Bez is aiming for a niche market

Aston Martin has not yet made a firm decision to produce the Rapide, though "if we build it, then we will build it in [about] 36 months' time", Mr Bez says.

If so, the car could hit the road by the end of 2007 or during 2008.

That would mean it would arrive in the market place before the Porsche Panamera, which will not turn up until 2009.

Not that the two will be rivals, though.

"I'm not looking at them," Mr Bez says. "We are different."

Nice game

Indeed, Aston's Rapide would cost about $250,000, according to Mr Bez, and this, a Porsche spokesman says, "is a price category we're not looking at for the Panamera".